In principle, link_subvol() can be given an abitrary string as the name of the saved subvolume. It copies it into a fixed-size stack buffer and then uses it as dirent names without testing its length.
This limits its length to BTRFS_NAME_LEN. This was found by static analsys. Signed-off-by: Zach Brown <[email protected]> --- btrfs-convert.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/btrfs-convert.c b/btrfs-convert.c index 221dd45..edef1bd 100644 --- a/btrfs-convert.c +++ b/btrfs-convert.c @@ -1428,10 +1428,15 @@ static struct btrfs_root * link_subvol(struct btrfs_root *root, struct btrfs_key key; u64 dirid = btrfs_root_dirid(&root->root_item); u64 index = 2; - char buf[64]; + char buf[BTRFS_NAME_LEN + 1]; /* for snprintf null */ + int len; int i; int ret; + len = strlen(base); + if (len < 1 || len > BTRFS_NAME_LEN) + return NULL; + path = btrfs_alloc_path(); BUG_ON(!path); @@ -1467,18 +1472,22 @@ static struct btrfs_root * link_subvol(struct btrfs_root *root, key.offset = (u64)-1; key.type = BTRFS_ROOT_ITEM_KEY; - strcpy(buf, base); + memcpy(buf, base, len); for (i = 0; i < 1024; i++) { - ret = btrfs_insert_dir_item(trans, root, buf, strlen(buf), + ret = btrfs_insert_dir_item(trans, root, buf, len, dirid, &key, BTRFS_FT_DIR, index); if (ret != -EEXIST) break; - sprintf(buf, "%s%d", base, i); + len = snprintf(buf, ARRAY_SIZE(buf), "%s%d", base, i); + if (len < 1 || len > BTRFS_NAME_LEN) { + ret = -EINVAL; + break; + } } if (ret) goto fail; - btrfs_set_inode_size(leaf, inode_item, strlen(buf) * 2 + + btrfs_set_inode_size(leaf, inode_item, len * 2 + btrfs_inode_size(leaf, inode_item)); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); @@ -1487,13 +1496,13 @@ static struct btrfs_root * link_subvol(struct btrfs_root *root, ret = btrfs_add_root_ref(trans, tree_root, root_objectid, BTRFS_ROOT_BACKREF_KEY, root->root_key.objectid, - dirid, index, buf, strlen(buf)); + dirid, index, buf, len); BUG_ON(ret); /* now add the forward ref */ ret = btrfs_add_root_ref(trans, tree_root, root->root_key.objectid, BTRFS_ROOT_REF_KEY, root_objectid, - dirid, index, buf, strlen(buf)); + dirid, index, buf, len); ret = btrfs_commit_transaction(trans, root); BUG_ON(ret); -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
